Magnetic contactor utilizing shading coils for retaining the front and back plates of the housing in spaced assembled relation



1958 D F. WILLCOX 3,364,448

MAGNETIC CONTACTCIR UTILIZING SHADING COILS FOR RETAINING THE FRONT AND BACK PLATES OF THE HOUSING IN SPACED ASSEMBLED RELATION Filed Sept. 26, 1966 2 Sheets-Sheet 1 F9 1W .72

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Jan. 16, 1968 D. F. WILLCOX 3,364,448

MAGNETIC CONTACTOR UTILIZING SHADING COILS FOR RETAINING THE FRONT AND BACK PLATES OF THE HOUSING IN SPACED ASSEMBLED RELATION 2 Sheets-Sheet 2 Filed Sept. 26, 1966 l I Z3 Patented Jan. 16, 1968 3,364,448 MAGNETIC CONTACTOR UTILIZING SHADING CQILS FOR RETAINING THE FRONT AND BACK PLATES OF THE HUUSING IN SPACED ASSEMBIJED RELATION Dale F. Wilicox, Aurora. Ill., assignor to Furnas Electric Company, Batavia, llL, a corporation of Delaware Filed Sept. 26, 1966, Ser. No. 582,012 7 Claims. (Cl. 335-126) The invention relates to electric switches and has reference more particularly to switch apparatus of the magnetic contactor type and which has a resiliently mounted armature for positive contact with magnet field piece.

The present design of magnetic contactor has several features which will provide an electric switch that can be economically manufactured in production quantities although rugged and durable in construction, a switch that can be readily disassembled for replacement of parts or for repairs, and a switch that will operate successfully for many years without requiring periodic attention.

Another object of the invention is to provide a magnetic contactor which will embody a minimum number of parts and wherein the magnet shading coils and the stationary contact members are additionally employed as retaining means for retaining the front and back plates of the housing in spaced assembled relation.

Another object resides in the provision of copper shading coils for the magnet field piece of a magnetic contactor and which will be suspended in air for reducing magnetic heating so as to substantially eliminate breakage.

A further object is to provide a magnetic contactor wherein the reciprocating contact carrier is guided by the front and back plates of the housing and also by the stationary contact members. Positive guiding of the contact carrier at points relatively close to the contact reduces contact wear and lowers arcing temperatures.

Another object is to provide a magnetic contactor of the type described which will embody a reciprocating contact carrier having a resiliently mounted armature to absorb the shock in opening and closing, and wherein the pro-stroke and overtravel of the contacts are fixed by die punched front and back plates.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts- FIGURE 1 is a front elevational view of a magnetic contactor constructed in accordance with and which ernbodies the improved features of the invention;

FIGURE 2 is a side elevational view of the contactor shown in FIGURE 1 with the contact carrier, the armature, and the contacts in open position;

FIGURE 3 is a rear elevational view of the contactor of the invention;

FIGURE 4 is a vertical sectional view taken substan tially along line 44 of FIGURE 1;

FIGURE 5 is a vertical sectional view taken substantially along line 5-5 of FIGURE 2;

FIGURE 6 is a view similar to FIGURE 5 but illustrating the position of the parts upon initial closing of the contacts;

FIGURE 7 is a view similar to FIGURE 6 but illustrating the position of the parts when the armature is in full contact with the magnet field piece;

FIGURE 3 is a horizontal sectional view taken substantially along line 8-8 of FIGURE 5; and

FIGURE 9 is a horizontal sectional view taken substantially along line 99 of FIGURE 5.

The magnetic contactor of the invention is shown in front elevation in FIGURE 1, and in side elevation in FIGURE 2, and by observing these figures it will be understood that the housing for the contactor essentially consists of a front plate 10 and a back plate 11. These plates may be formed of Bakelite with a linen base for strength and both plates are die cut to produce the desired openings for receiving shading coils and stationary contact members which assist in retaining the front and back plates in spaced assembled relation as will be more fully described.

The magnet field piece 12 of the coil assembly 14 is generally U-shaped as best shown in FIGURES 5 and 6, and the said frame has a base part 15 and side leg members 16 and I7. The frame member carries a center pole piece 18, the frame member and the pole piece being preferably formed of silicon steel, and the pole piece being laminated for the most eflicient operation. The laminations are held together by the rivets 19. The coil 20 is carried by the center pole piece with an insulating spool 21 being interposed between, and the pole piece 18 and the leg members 16 and 17 all terminate at the same horizontal level so as to allow full contacting engagement with the armature 22 which is carried by the vertically reciprocable contact carrier 23.

Referring again to the U-shaped member 12 which forms the magnet field piece of the coil assembly, the same is provided with projections such as 24 and 25, FIGURES 1 and 3, the projections 24 extending into openings in the front plate 10 and the projections 25 extending into openings in the rear plate 11. The projections thus serve to properly locate the coil assembly. The terminals of the coil assembly are indicated by the numerals 26, and the same are made accessible since they extend through the large opening 27.

In accordance with the invention coils 28 and 30, FIGURE 8, for the magnetic field piece 12 aresuspended in air and said elements have the additional function of assisting in retaining the front and back plates in spaced assembed relation. Both elements have a head part 39 which engage the front plate lit and each element is formed with a rear shoulder which engages the rear plate 11. A tab 32 projects from the shoulder area and each tab extends through an opening in the back plate. When the tab is twisted a lock is provided which will retain the back plate in assembled relation. The shading coil element 23 has an elongated opening 36 for the copper shading receiving a part of the leg 16', and a slot 34 receives a smaller part of the leg 16. The shading coil element is similar although the elongated opening 36 and the slot 34 are reversed. By suspending the shading coils in the air, magnetic heating is reduced with the result that the breakage of the shading coils is reduced if not substantially eliminated.

The contact carrier 23 is guided in its reciprocating movement by the front and back plates 10 and 11, and

also by the stationary terminal members 35 and 36. As shown in FIGURE 4 the carrier '23 is provided with side projections '37 which ride in openings 38 in the front and back plates respectively. The terminal members 35 and 36 are riveted to the front plate and said members extend horizontally to the rear and enter openings in the rear plate. Two top members 35 are located on respective sides of the carrier as are also the tvvo bottom members 36, see FIGURES 5, 6 and 7. Here again, each member is formed with a rear shoulder similar to that formed on the shading coils and the resulting tab 40 extends through an opening in the rear plate. Upon being twisted the tab serves as a lock for the rear plate. The front depending end of each stationary terminal member carries a terminal screw 41 and the members 35 are each provided with a contact 42, whereas the terminal members 36 are each provided with a contact 43. The terminal members are spaced so that the carrier rides between the members with the result that the carrier is guided thereby in addition to being guided by the side projections 37.

The armature 22 of metal is resiliently retained on the carrier by means ot the fiat spring member 44, FIGURE 9, which is retained in place by having a center opening which receives the circular stud or projection 45 provided by the carrier. The ends of the flat spring member project upwardly and enter openings 46 in the armature and this feature also assists in retaining the fiat spring member in place. The spring member yieldingly holds the armature up against the overhanging ears 47 at the carrier. Although the armature is securely retained by the carrier, it is tree to pivot to a limited extent So as to assure tfull contact of the armature with the magnet field piece. Also, the resilient mounting of the armature on the carrier serves to take up shock on closing as well as on opening of the contacts.

Bridging members 48 and 50 are also resiliently carried by the reciprocable contact carrier 23 and each bridging member has a pair of contacts fixed thereto such as contacts 51 for member 48 and contacts 52 for member 50. The bridging members extend through openings in the carrier so that a contact is located on each side of the carrier. The coil springs 53 are seated on the lower surface of the openings and they extend upwardly to engage a bridging member to thus yieldingly hold the member up against the top surface of the opening.

in FIGURE it will be under-stood that the coil assembly is deenergized so that the carrier is in down position with the contacts open. Upon energizing the coil 20 the field piece 12 becomes magnetic and attracts the armature 2/2. The carrier is caused to move upwardly and in so doing the contacts are closed, with the contacts 51 carried by the bridging member 48 engaging the stationary contacts 42. In a similar manner the contacts 52 carried by the bridging member 50 will engage the stationary contacts 43. Although the contacts are closed as shown in FIGURE 6 the armature has not as yet fully seated itself on the magnet field piece. Further attraction of the armature thus takes place and as evident from FIGURE 7 this additional upward movement of the carrier causes compression of the coil springs 53. Thus the closed contacts are subjected to resilient compression to assure good conductivity.

When the coil 20 is dc-magnetized, the carrier 23 drops to open the contacts. However, down movement of the carrier is limited by the stop projections 54 on the carrier and which engage the top stationary terminal members 35.

The housing for the contactor of the invention consists essentially of the front and back plates and which are die punched to provide the necessary openings. Accordingly, the pre stroke and overtravel of the contacts are fixed and the same cannot vary from unit to unit since all of the openings are punched with one stroke and are as accurate as the die. The shading coils and the stationary contact members perform a dual function since they retain the front and back plates in spaced assembled relation. Also, the reciprocable contact carrier is guided by the plates of the housing since the projections 37 ride within the sllots 38 and the said carrier is additionally guided by the stationary contact members which 'are disposed on respective sides of the carrier.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings as various other forms of the device 'will, of course, be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. In a magnetic confiaotor, the combination comprising; a housing including front and back plates, a coil assembly mounted in said housing providing 'a magnet field piece, a reciprocable contact carrier, an armature carried by the "carrier and adapted to contact the magnet field piece when the coil assembly is energized, shading coils for the magnet field piece, said shading coils extending between the front and back plates of the housing and having contact therewith to lock the plates in spaced assembled relation, and means provided by the carrier having coacting relation with the front and back plates for guiding the carrier in its reciprocating movements.

2. A magnetic c'ontactor as defined by claim '1, addit-ionally including stationary contact members which also extend between the front and back plates and assist the shading coils in holding the front and back plates in spaced assembled relation, said stationary contact members being located on respective sides of the reciprocable contact car-rier and additionally tfunction'ing as guiding means for the carrier.

3. A magnetic 'contactor as defined by claim 1, additionally including stationary contact members extending between the front and back plates and having a secured relation therewith, said stationary contact members being located on respective sides of the reciprocable contact carrier, a contact provided by each of said members, a bridging member carried by the contact carrier and providing contacts for respectively engaging those on the stationary contract members, and resilient means yieldingly holding the bridging member in assembled relation on the carrier.

4. A magnetic contactor as defined by claim 1, wherein the means provided by the carrier for guiding the carrier includes projections on the carrier and which ride in slots formed in the front and back plates, respectively.

5. A magnetic contactor as defined by claim 1, wherein the means provided by the carrier for guiding the carrier includes projections on the carrier and which ride in slots formed in the front and back plates, respectively, and additionally including stationary contact members which also extend between the front and back plates and assist the shading coils in holding the front and back plates in spaced assembled relation, said stationary contact members being located on respective sides of the reciprocable contact carrier and additionally functioning as guiding means for the carrier.

6. In a magnetic contactor, the combination comprising; a housing including front and back plates, a coil assembly mounted in said housing providing a magnet field piece, a reciprocable contact carrier, an armature mounted on the carrier and adapted to contact the magnet field piece when the coil assembly is energized, shading coils for the magnet field piece, said shading coils extending between the front and back plates of the housing and having contact therewith to lock the plates in spaced assembled relation, means provided by the carrier having coacting relation with the front and back plates for guiding the carrier in its reciprocating movements, a fiat resilient member interposed between the carrier and said armature, said resilient member comprising the means which mounts the 5 6 armature on the carrier, and said resilient member addi- References Cited tionally serving to absorb the shock incident to the arrna- UNITED STATES PATENTS t tt'gth tfild' h h '1' $55? m e magne e place W en t e 15 2,434,096 1/19481 \Ayers '3 35 2s 1 7. A magnetic contactor as described in claim 6, Where 5 2,468,052 4/1949 Flsher 335 245 in the flat resilient member is held in place by having a 33701301 8/1966 Bengtsson 335 129 center opening which receives a stud projecting from the carrier and by having bent ends which enter respective BERNARD GILHEANY P'lmary Exammer' openings in the armature. H. BROOME, Assistant Examiner. 

1. IN A MAGNETIC CONTACTOR, THE COMBINATION COMPRISING; A HOUSING INCLUDING FRONT AND BACK PLATES, A COIL ASSEMBLY MOUNTED IN SAID HOUSING PROVIDING A MAGNET FIELD PIECE, A RECIPROCABLE CONTACT CARRIER, AN ARMATURE CARRIED BY THE CARRIER AND ADAPTED TO CONTACT THE MAGNET FIELD PIECE WHEN THE COIL ASSEMBLY IS ENERGIZED, SHADING COILS FOR THE MAGNET FIELD PIECE, SAID SHADING COILS EXTENDING BETWEEN THE FRONT AND BACK PLATES OF THE HOUSING AND HAVING CONTACT THEREWITH TO LOCK THE PLATES IN SPACED ASSEMBLED RELATION, AND MEANS PROVIDED BY THE CARRIER HAVING COACTING RELATION WITH THE FRONT AND BACK PLATES FOR GUIDING THE CARRIER IN ITS RECIPROCATING MOVEMENTS. 